# CSS: “background-image”: X is not a “background-image” value.
> Canonical HTML version: https://rocketvalidator.com/html-validation/css-background-image-x-is-not-a-background-image-value
> Attribution: Rocket Validator (https://rocketvalidator.com)
> License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
The `background-image` CSS property accepts a specific set of value types defined by the CSS specification. The most common are `none` (the default, meaning no image), the `url()` function pointing to an image file, and gradient functions like `linear-gradient()` or `radial-gradient()`. When the validator encounters a value that doesn't match any of these patterns, it flags the error.
This issue often appears in inline `style` attributes within HTML, which is where the W3C HTML Validator checks your CSS. Common mistakes include providing a bare filename without `url()`, forgetting parentheses or quotes, using incorrect gradient syntax, or introducing typos in CSS function names.
Fixing this matters for several reasons. Browsers may silently ignore an invalid `background-image` declaration entirely, meaning your intended background simply won't appear. This leads to broken visual designs that can be difficult to debug. Additionally, invalid CSS can cause parsing errors that may affect subsequent declarations in the same rule block.
### How to fix it
1. **Wrap image paths in `url()`** — A bare filename like `background-image: photo.jpg` is invalid. It must be `background-image: url("photo.jpg")`.
2. **Use proper quoting** — While quotes inside `url()` are technically optional for simple paths, always use them for paths containing spaces, parentheses, or special characters. Single or double quotes both work.
3. **Check gradient syntax** — If using gradients, ensure the function name is correct (e.g., `linear-gradient`, not `linear-gradiant`) and the arguments follow valid syntax.
4. **Use recognized keywords** — The only non-function keyword accepted is `none`. Values like `transparent`, `auto`, or arbitrary strings are not valid for this property.
## Examples
### Incorrect: bare filename without `url()`
```html
Content here
```
### Incorrect: misspelled function name
```html
Content here
```
### Incorrect: missing parentheses in `url`
```html
Content here
```
### Incorrect: invalid keyword
```html
Content here
```
### Correct: using `url()` with a file path
```html
Content here
```
### Correct: using `none` to explicitly set no background image
```html
Content here
```
### Correct: using a gradient function
```html
Content here
```
### Correct: multiple background images
```html
Content here
```
### Correct: using a `
Welcome